Graphene is a flat monolayer of sp2-hybridized carbon atoms tightly packed into a two-dimensional (2D) honeycomb structure. It has attracted growing attention owing to its superior thermal conductivity, electrical conductivities, and mechanical strength that rivals the notable in-plane values of graphite (˜3000 W/m K, 8000 S/m, and 1000 GPa, respectively).
In addition, graphene is a zero-bandgap semiconductor with a linear band structure near the k-point. At high optical intensities, the photo-generated carriers block further absorption. The high frequency conductivity for Dirac fermions in graphene should be a universal constant equal to e2/4 h. This unique property gives graphene a universal 2.3% linear optical absorption that makes it transparent, despite its high conductivity.
Much effort has focused on its fabrication since its first creation by micro-exfoliation in 2004. Besides micro-exfoliation, fabricating methods developed include thermal chemical vapor deposition techniques, plasma enhanced chemical vapor deposition, chemical methods, thermal decomposition of SiC, un-zipping CNTs, etc.
CN103508447 discloses a preparation method of graphene. The method comprises the steps of: obtaining graphene oxide and a substrate; preparing a paste of graphene oxide and coating the paste on the surface of the substrate; and preparing the graphene by a laser reduction method. Nevertheless, this method needs a special gaseous environment during the laser reduction process, leading to increase of production cost. In addition, the graphene formed is easily peeled off from the substrate.
WO2012128748 discloses a method to fabricate patterned graphite oxide films. The method comprises the steps of: selecting a graphite oxide membrane, wherein the graphite oxide membrane is a freestanding graphite oxide membrane; forming a pattern on the graphite oxide membrane to form a patterned graphite oxide membrane, wherein the pattern is formed by reducing a portion of the graphite-oxide membrane to conducting reduced graphite oxide; and forming a device that comprises the patterned graphite oxide membrane, and cutting a pattern from tape. Nevertheless, it is complicate and unsecure to attach the freestanding graphite oxide membrane on other components by using tape for device formation.
CN101723310 discloses a method for preparing a conductive graphene oxide using micro-nano structure light processing. The method comprises the steps of: forming graphene oxide on a substrate by spin coating, dip coating or drop coating; setting up nanofabrication laser system; and reducing the graphene oxide on the substrate into graphene. The laser system operates in a double beam interference mode, and interference fringes are used. Nevertheless, under such system, the patterned size is very small (50×50 μm) in micro (μm) scale and the processing efficiency is low. In addition, as point-to-point and interference laser scanning system are used to fabricate the micro-nano structures, the fabricated surface will thus be discrete in nature, so surface quality (also product surface details) is then limited.
Consequently, there is an unmet need to have a method for fabricating conducting graphene oxide devices or circuits being applicable for different applications, and in an efficient way.